LispWorks was developed by the UK software company Harlequin Ltd. and first published in 1989[1]. Harlequin ultimately spun off its Lisp arm as Xanalys, which took over management and rights to LispWorks. In January 2005, the Xanalys Lisp team formed LispWorks Ltd. to market, develop, and support the LispWorks software.

many of the libraries are written using the Common Lisp Object System and can be extended by the user (by writing subclasses and new methods)

The Enterprise edition also includes KnowledgeWorks, which adds Prolog features to Lisp; the CommonSQL database interface; and a CORBA binding. The Enterprise edition is also available as a 64bit implementation.

In September 2009, it had been announced that LispWorks 6 would support concurrent threads and the CAPI graphics toolkit has been extended to support GTK+[2]. LispWorks 6 was released January 2010[3].